Screening Woody Species for Afforestation of Degraded Croplands in the Sudano-Sahelian Zone of Benin
Florent Noulekoun1, Jesse B. Naab2, John Lamers1, Asia Khamzina1
1University of Bonn, Center for Development Research (ZEF), Germany
In the Sudano-Sahelian zone of Benin, where deforestation and cropland soil degradation persist at alarming rates, the re-introduction of trees on degraded lands may offer great opportunities to sustain farming systems. To improve the understanding of the vital process of tree establishment and early growth, we conducted an afforestation experiment with five woody species on degraded cropland. The survival and growth response to manuring (1kg plant-1) and drip irrigation (0.5 liter of water sapling-1 day-1) were monitored over the first 15 months, covering two growing seasons and one dry season. The overall high survival rates (>60%) with a very low incidence rate (<0.01%) indicated a successful establishment of all species, particularly Jatropha curcas, Leucaena leucocephala and Moringa oleifera which had the highest rates (67-100%). Supplemental irrigation reduced by ten-folds the mortality rate of the most drought-sensitive species Parkia biglobosa during the dry season. Significantly higher relative growth rates were recorded for L. leucocephala, M. oleifera and J. curcas (0.41-0.52 g g-1month-1) than for Anacardium occidentale and P. biglobosa (0.31 and 0.33 g g-1month-1). The plants responded to fertilization and irrigation treatments by enhancing the shoot growth, as observed in both fast-growers (L. leucocephala, M. oleifera and J. curcas) and slow-growers (A. occidentale and P. biglobosa) during wet season. Increasing belowground development was observed in slow-growers during dry and wet seasons. Overall, the five examined species showed great potential for afforestation of degraded croplands, and manuring and irrigation were key for boosting and facilitating early growth and establishment of seedlings.
Keywords: Degraded cropland, morphological traits, multipurpose tree, northern Benin, survival rate
Contact Address: Florent Noulekoun, University of Bonn, Center for Development Research (ZEF), Walter-flex-Str.3, 0049 Bonn, Germany, e-mail: florentnoulekounyahoo.fr